Drone functional additions + project setup:
Functional
 - drone brick category
 - takeoff brick
 - settings option to enable/disable the drone bricks
 - drone support on PrestageActivity (incomplete)
Project setup:
 - reference CatroidDrone from catroid (parrot source code)
 - Adde DroneControlService, dependent classes and native libraries
Update README.md

add link to JIRA Bugtracker
add gradle lint config
Merge pull request #968 from Catrobat/adaptGradleBuildfile

add gradle lint config
Drone PARROT_License added
Drone connection process implemented
Drone refactoring + new functions + tests + project setup:
 - connection process improvements
 - change ARDRONE_SUPPORT  from 0x10 to 0x20
 - handing extra from Prestage to Stage to connect to Drone on Stage
 - drone brick Actions use act(...) instead of update(...)
 - added play led animation (updated native libs)
 - renamed TakeOff brick and corresponding XML's
 - fixed wrong naming of bricks
 - imported changes from native project->different led animations are now possible
 - all handle play buttons now direct the drone extras to the stage
 - applied coding standard to parrot sources
 - fixed style and code tests
 - Parrot sources catroid/src/com/parrot/* are not checked for license header
 - added missing translations
 - removed unused strings
 - DroneControlService calls optimized
 - stage activity droneConnection fixed
 - updated native libs
Project Setup
 - Added native libs to the catroid/libs-natives/gdx-natives-for-gradle.jar file.
   For more Information take a look at:
   http://stackoverflow.com/questions/16683775/include-so-library-in-apk-in-android-studio
Drone features added:
 - drone bricks added
 - new color for drone bricks
 - SettingsActivity refactored
 - drone preference string changed
Drone functions + standard project + tests + PreStage checks:
Functions:
 - StartDroneService only when drone is on the network
Standard project:
 - drone standard project
   (Note: only created when 'Pocket Code' folder is empty and using app with debug flag enabled)
 - new LED sprite for drone standard project
 - delete and recreate drone standard project on every startup
 - positioned sprites in one line on the bottom
Tests:
 - Prestage activity checks for drone connection
 - fixed source tests
Prestage checks:
 - control battery charge before going to stage
Drone demo project + bricks refactoring:
Demo project:
 - drone demo project
 - speed formular field for forward brick
Refactoring:
 - turn left and right brick & action
 - add power to bricks
Drone libs + refactoring + tests:
Libs:
 - Powermock libs updated
Refactoring:
 - DroneProxyInterface and DroneControlServiceInterface for better testability
 - fixed actions
Tests:
 - DronePlayLedAnimationTest
Drone functional + test:
Test:
 - Demo BrickTest implemented
Functional:
 - DroneControlService calls in Actions moved from update() to begin()
Drone refactoring:
 - changed library references to relative paths
 - LED-animation bug fixed
 - DroneProxywrapper interface applied
 - prepared DroneProxy for testing
Drone standard project extended
Drone tests + demo project:
Tests:
 - drone connection process partially mocked
 - SimpleDroneTest
Demo project:
 - turn icons with transparent background
Drone refactoring: bricks & actions
Drone libs + tests:
Libs:
 - Mockito libraries added
Tests:
 - First mockito tests
 - DroneDemoTest
 - DroneFlipTest added
Drone refactoring + project/test setup:
 - removed DroneProxyWrapper, DroneProxyInterface, IDroneServiceWrapper
 - fixed classpath
 - Android 4.4 Mockito fix
Drone tests + refactoring:
 - dronetests removed
 - toggle drone bricks test
 - UI BricksMoveTests, BricksFactory
 - poweredit test
Drone tests:
 - first robotium tests added
 - TakeOff & Land test added
 - DroneMoveUpTest
 - DroneStageTest
 - DroneMoveForwardTest
 - CheckAssertionsTest adapted